Different boxes sound better with different amps/guitars anyway. If poss find a shop with a good range of pedals at reasonable prices (window shopping required) and take your guitar and amp in to try them. I didn't follow my own advice but I like my Crybaby Wah. I believe there's some other Crybaby (I think) that's designed to work very well with high gain (Dime bag Darrell uses it), you may find that he wah effect becomes less noticeable with high gain.
Morley wah's apparently have an optical set up which lasts longer but wah pedals are very simple affairs and it doesn't cost much to replace a worn variable resistor. Happy shopping!